The invention relates to an apparatus for the heat treatment of foods, particularly for the cooking of meals, by means of steam or a steam/air mixture with a cooking area and a steam supply regulatable subject to a sensor.
Various constructional embodiments of such apparatuses for the heat treatment of foods or meals are known (cf e.g. German Pat. No. 2,731,191 and German Utility Model No. 8,131,827). Normally, in the case of such apparatuses for the purpose of heat treating foods, e.g. for thawing deep-frozen foods, or for cooking meals, i.e. for boiling, baking or roasting purposes, water vapour is introduced into the cooking area and mixes with the air present in the latter or partially displaces the said air.
The steam and steam/air mixtures gives off its heat to the product being cooked, thawed, etc, the steam proportion condensing and the condensate can drain off by means of a steam trap normally issuing in the bottom of the cooking area. The steam "consumed" in this way is sent back into the cooking area by means of the steam supply system. This resupply requirement varies, as a function of the state of the product being cooked, thawed, etc so that it is advantageous to control or regulate the steam supply.
For regulating the steam supply, it has already been proposed (cf German Pat. No. 2,731,191), to fit a heat sensor of a temperature regulator in the steam trap enabling the steam supply to be regulated as a function of the temperature prevailing in the steam trap. An apparatus constructed according to this proposal generally leads to a satisfactory regulation of the steam supply in the cooking area, which permits economic and energy-saving operation. However, such an apparatus is not completely free from disadvantages under all conditions. Thus, at the heat sensor in the steam trap and which is at least partly simultaneously used for draining off fat or gravy running down from the meals, it is also possible for clogging to occur by the fat and gravy being deposited at the location of the heat sensor, so that the latter becomes encrusted. As a result, the measured temperature value is falsified. The steam trap can also partly become clogged as a result of careless operation of the apparatus, overloading of the cooking area or as a result of other circumstances, so that the heat sensor responds with a marked time lag. From the maintenance and cleaning standpoints, the arrangement of the heat sensor in the steam trap is not particularly advantageous, particularly, as is partly provided, the steam trap is subdivided into a condensate removal tube and a fat drain the latter e.g. being coupled by means of a displaceable sleeve to the steam trap. Depending on the heat sensor arrangement, the latter can only be reached with a certain effort, whilst bearing in mind that with increasing flow distance of the heat sensor from the cooking area, the regulation of the actual conditions is subject to an increasingly long time lag.
In view of the aforementioned shortcomings of known apparatuses of the aforementioned time, the problem of the present invention is to so construct and further develop such an apparatus that at any time, even under extreme conditions a reliable and sensitive regulation of the steam supply is possible, preferably accompanied by an improvement to maintenance conditions.